"We tried to get Novak Djokovic to be allowed to get an exemption, but that wasn't able to happen," Miami Open tournament director James Blake said.
The U.S. will bring a loaded squad to Delray Beach next month.
Tensions on the WTA Tour continue rising between some Ukrainian and Russian players.
Riding an 18-match winning streak, Daniil Medvedev shares a key to his focus.
Charging into his maiden Masters semifinal in Indian Wells reinforces Frances Tiafoe's major dream.
US Open champion cites one shot as major measuring stick.
'I saw a taste of the level where No.1 is at physically' says Raducanu after falling to Swiatek